JP2015022220A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens which is compact as a whole and offers a wide view angle and nonetheless requires less aberration correction for correcting image blur, and which can maintain high optical performance even when used in an anti-shake mode.SOLUTION: The zoom lens comprises, in order from the object side to the image side, first through third lens groups having negative, positive, and positive refractive power, respectively, an aperture stop, and fourth and fifth lens groups having negative and positive refractive power, respectively, where distance between each adjacent pair of lens groups changes while zooming, and the third lens group has an anti-shake lens section which moves in a direction having a component perpendicular to an optical axis to provide image blur correction. A focal length fw of the entire system at the wide angle end, a focal length fis of the anti-shake lens section, a distance Dis from an image-side lens surface of the anti-shake lens section to the aperture stop on the optical axis, and a distance DLw from a most object-side lens surface to a most image-side lens surface on the optical axis at the wide-angle end are each set appropriately.

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, and is suitable for an image pickup optical system used in an image pickup apparatus such as a digital camera, a video camera, a TV camera, a surveillance camera, and a silver salt film camera.

  An imaging optical system used in an imaging apparatus (camera) is required to be a small zoom lens that includes a wide shooting angle of view and has high resolution. Also, in this type of camera, various optical members such as a low-pass filter and a color correction filter are arranged between the rearmost part of the lens and the solid-state image sensor, so that the zoom lens used therefor has a relatively long back focus. Is required. Furthermore, it is desired that the zoom lens has a mechanism (anti-vibration mechanism) that compensates for image blur (image blur) that occurs when accidental vibration such as camera shake is transmitted to the zoom lens.

  As a zoom lens having a relatively long back focus and a wide angle of view, a negative lead type zoom lens in which a lens group having a negative refractive power is positioned on the object side is known. This negative lead type zoom lens has a feature that it is easy to shorten the close-up shooting distance. A negative lead type zoom lens, which is composed of a first lens group to a fourth lens group having negative, positive, negative, and positive refractive power in order from the object side to the image side, is known as a four-group zoom lens having an anti-vibration mechanism. (Patent Document 1).

  In Patent Document 1, image blurring is compensated by decentering a part of the second lens unit in a direction perpendicular to the optical axis. The negative lead type zoom lens is composed of first to fifth lens units having negative, positive, positive, negative, and positive refractive powers in order from the object side to the image side, and includes five groups having an anti-vibration mechanism. A zoom lens is known (Patent Document 2). In Patent Document 2, the fourth lens unit is decentered parallel to the direction perpendicular to the optical axis to compensate for image blur.

JP 2007-78834 A JP 2009-251112 A

  In recent years, zoom lenses used in image pickup apparatuses have been strongly demanded to have a wide angle of view, the entire lens system to be small, and to have an anti-vibration mechanism. In particular, when correcting the image stabilization lens unit for correcting image blur by moving the image stabilization lens in the direction perpendicular to the optical axis, the image stabilization is performed in order to reduce the size of the moving mechanism (anti-vibration mechanism) and save power. The lens part is required to be small and light.

  Further, there is a demand for maintaining good optical performance even during image stabilization, with less aberration fluctuations during image blur correction. In a zoom lens that performs image blurring by using a part of the zoom lens as an anti-vibration lens unit and decentering in the direction perpendicular to the optical axis, image blur can be corrected relatively easily.

  However, if the lens configuration of the zoom lens and the lens configuration of the anti-vibration lens unit to be moved for anti-vibration are not appropriate, the amount of decentration aberration generated during the anti-vibration increase, and the optical performance is greatly deteriorated. In addition, the drive mechanism becomes larger. For this reason, in a zoom lens having an anti-vibration mechanism, it is important to appropriately set the overall lens configuration, the anti-vibration lens unit configuration, and the like.

  For example, when the incident height from the optical axis of the off-axis ray passing through the anti-vibration lens unit becomes high, it becomes difficult to correct the aberration of the off-axis ray at the time of anti-vibration. In addition, when zooming from the wide-angle end to the telephoto end, if the distance between the aperture stop and the anti-vibration lens unit increases, the incident height from the optical axis of the off-axis light beam passing through the anti-vibration lens unit increases. It becomes difficult to correct aberrations of off-axis rays during shaking.

  For this reason, it is important to appropriately set the refractive power of the image stabilizing lens unit, the distance between the aperture stop and the image stabilizing lens unit, and the like. If these configurations are not set appropriately, it will be very difficult to reduce the vibration isolation mechanism and maintain high optical performance during vibration isolation while reducing the overall system size and widening the angle of view. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens that is small in size and has a wide angle of view and that can reduce aberration correction during image blur correction and maintain high optical performance even during image stabilization.

The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, an aperture stop, and a negative refractive power. The zoom lens includes a fourth lens group and a fifth lens group having a positive refractive power, and the distance between adjacent lens groups changes during zooming.
The third lens group includes a vibration-proof lens unit that moves in a direction having a component perpendicular to the optical axis during image blur correction. The focal length of the entire system at the wide-angle end is fw, and the image stabilization The focal length of the lens unit is fis, the distance on the optical axis from the image side lens surface of the image stabilizing lens unit to the aperture stop is Dis, and from the most object side lens surface to the most image side lens surface at the wide angle end. When the distance on the optical axis is DLw,
1.5 <| fis / fw | <9.5
0.00 <Dis / DLw <0.25
It satisfies the following conditional expression.

  According to the present invention, it is possible to obtain a zoom lens that is small in size and has a wide angle of view and that has little aberration correction during image blur correction and can maintain high optical performance even during image stabilization.

Sectional view of the lens at the wide-angle end of Embodiment 1 of the present invention Longitudinal aberration diagram at the wide-angle end and the telephoto end of Example 1 of the present invention Lateral aberration diagram of the first embodiment of the present invention at the reference time and during vibration isolation Sectional view of the lens at the wide-angle end of Embodiment 2 of the present invention Longitudinal aberration diagram at the wide-angle end and the telephoto end according to the second embodiment of the present invention Lateral aberration diagram of the second embodiment of the present invention at the reference time and during vibration isolation Sectional view of the lens at the wide-angle end of Embodiment 3 of the present invention Longitudinal aberration diagram at the wide-angle end and the telephoto end according to the third embodiment of the present invention Lateral aberration diagram of Example 3 of the present invention at the reference time and at the time of image stabilization Cross-sectional view of a lens at a wide angle end according to Embodiment 4 of the present invention Longitudinal aberration diagram at the wide-angle end and the telephoto end according to the fourth embodiment of the present invention Lateral aberration diagram of the fourth embodiment of the present invention at the reference time and during vibration isolation Schematic diagram of main parts of an imaging apparatus of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, an aperture stop, and a negative refractive power. It is composed of a fourth lens group and a fifth lens group having a positive refractive power. The zoom lens changes the interval between adjacent lens groups during zooming. The third lens group has an anti-vibration lens unit that moves in a direction having a component perpendicular to the optical axis during image blur correction.

  In order to reduce the size of the anti-vibration lens unit in the negative lead type zoom lens preceded by the lens unit having a negative refractive power, the lens components after the second lens unit having a small effective lens diameter are selected as the anti-vibration lens unit. Good to do. In order to reduce the weight of the anti-vibration lens unit, the anti-vibration lens unit is preferably composed of one or two lenses.

  When the anti-vibration lens unit is composed of a small number of lenses, the refractive power of the anti-vibration lens unit must be weakened in order to suppress aberration fluctuations during image stabilization. However, if the refractive power of the image stabilizing lens unit is weakened, the amount of drive of the image stabilizing lens unit increases during image stabilization, and the drive system for driving the image stabilizing lens unit tends to increase in size.

  Therefore, in the present invention, in order to reduce the size and weight of the anti-vibration lens unit, to reduce the size of the entire lens system, and to maintain high optical performance, the anti-vibration lens unit has an optical arrangement that is easy to miniaturize, and aberration fluctuations during image stabilization occur. The refractive power of the anti-vibration lens unit is appropriately set so as to be relatively small.

  In the zoom lens according to the present invention, the lens component in the vicinity of the aperture stop is the anti-vibration lens unit Gis, and the anti-vibration lens unit Gis is shifted so as to have a component in the direction perpendicular to the optical axis. Then, the refractive power of the anti-vibration lens unit Gis is appropriately set. That is, by arranging the image stabilizing lens unit Gis in the vicinity of the aperture stop SP, the incident height of off-axis rays passing through the image stabilizing lens unit Gis is lowered, and the effective lens diameter is reduced. Furthermore, as will be described later, the refractive power is arranged so as to reduce the deterioration of the aberration around the screen that occurs during image stabilization.

  FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to the first exemplary embodiment. FIGS. 2A and 2B are longitudinal aberration diagrams at the wide-angle end and the telephoto end (long focal length end) of the zoom lens of Example 1, respectively. 3A and 3B are lateral aberration diagrams at the wide-angle end and the telephoto end, respectively, of the zoom lens of Example 1, and FIGS. 3C and 3D are shakes of the zoom lens of Example 1, respectively. FIG. 10 is a lateral aberration diagram at the wide-angle end and at the telephoto end during image stabilization when the inclination at an angle of 0.3 degrees is corrected.

  FIG. 4 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the second exemplary embodiment. 5A and 5B are longitudinal aberration diagrams at the wide-angle end and the telephoto end, respectively, of the zoom lens according to the second embodiment. 6A and 6B are lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 2, respectively. FIGS. 6C and 6D are shakes of the zoom lens of Example 2, respectively. FIG. 10 is a lateral aberration diagram at the wide-angle end and at the telephoto end during image stabilization when the inclination at an angle of 0.3 degrees is corrected.

  FIG. 7 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the third exemplary embodiment. 8A and 8B are longitudinal aberration diagrams at the wide-angle end and the telephoto end of the zoom lens according to Embodiment 3, respectively. FIGS. 9A and 9B are lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Embodiment 3, and FIGS. 9C and 9D are shakes of the zoom lens of Embodiment 3, respectively. FIG. 10 is a lateral aberration diagram at the wide-angle end and at the telephoto end during image stabilization when the inclination at an angle of 0.3 degrees is corrected.

  FIG. 10 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the fourth exemplary embodiment. FIGS. 11A and 11B are longitudinal aberration diagrams at the wide-angle end and the telephoto end of the zoom lens according to Embodiment 4, respectively. FIGS. 12A and 12B are lateral aberration diagrams at the wide-angle end and the telephoto end of the zoom lens of Example 4, and FIGS. 12C and 12D are shakes of the zoom lens of Example 4, respectively. FIG. 10 is a lateral aberration diagram at the wide-angle end and at the telephoto end during image stabilization when the inclination at an angle of 0.3 degrees is corrected. FIG. 13 is a schematic diagram of a main part of a digital camera (image pickup apparatus) including the zoom lens according to the present invention. FIG. 13 is a schematic diagram of a main part of a digital camera (image pickup apparatus) including the zoom lens according to the present invention.

  The zoom lens of each embodiment is an imaging optical system used in an imaging apparatus (optical apparatus) such as a digital still camera, a video camera, and a silver salt film camera. In the lens cross-sectional view, the left side is the object side (front), and the right side is the image side (rear).

  i represents the order of the lens groups from the object side to the image side, and Li represents the i-th lens group. L1 is a first lens group having a negative refractive power (optical power = reciprocal of focal length), L2 is a second lens group having a positive refractive power, and L3 is a third lens group having a positive refractive power. The third lens unit L3 includes an anti-vibration lens unit Gis having a positive or negative refractive power. L4 is a fourth lens group having a negative refractive power, and L5 is a fifth lens group having a positive refractive power. SP is an aperture stop for adjusting the amount of light, and is disposed on the image side of the third lens unit L3.

  IP is an image plane, and when used as an imaging optical system of a video camera or a digital still camera, the imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is a silver salt film camera. Corresponds to the film surface.

  Each longitudinal aberration diagram shows spherical aberration, astigmatism, distortion, and lateral chromatic aberration in order from the left. In the diagrams showing spherical aberration and lateral chromatic aberration, the solid line represents the d line (587.6 nm), and the broken line represents the g line (435.8 nm). In the diagram showing astigmatism, the solid line S represents the d-line sagittal image plane, and the broken line M represents the d-line meridional image plane. Moreover, the figure which shows distortion represents the distortion in d line | wire. In the lateral aberration diagram, the solid line represents the d-line meridional image plane, and the broken line represents the d-line sagittal image plane. Fno is the F number, ω is the half angle of view (degrees) of the shooting angle of view, and hgt is the image height.

  In each embodiment, the wide-angle end and the telephoto end have a zoom lens unit (in each embodiment, the second lens unit L2, the third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5). The zoom position when positioned at both ends of the movable range on the optical axis. During zooming from the wide-angle end to the telephoto end, each lens group moves as indicated by the arrows in the lens cross-sectional view. Each lens group has a smaller distance between the first lens group L1 and the second lens group L2 and a larger distance between the third lens group L3 and the fourth lens group L4 at the telephoto end than at the wide-angle end. The lens unit L4 and the fifth lens unit L5 are moved so that the distance between them is small.

  Specifically, during zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves along a convex locus on the image side. The second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 are all moved toward the object side. Note that the third lens unit L3 and the fifth lens unit L5 may move along the same locus (integrally) in order to simplify the mechanism in addition to moving along different locuses. Focusing from infinity to short distance is performed by moving the second lens unit L2 to the image side as indicated by an arrow Focus. The second lens unit L2 includes one positive lens and facilitates rapid focusing.

  In each embodiment, when zooming from the wide-angle end to the telephoto end, the fifth lens unit L5 closest to the image side moves to the object side, and therefore, the back focus is the shortest at the wide-angle end in the entire zoom range.

  Therefore, a refracting power arrangement is employed such that the image side principal point position is located closer to the image side so as to ensure a predetermined length of back focus at the zoom position at the wide angle end. That is, the entire lens system is a strong retrofocus type at the zoom position at the wide-angle end. Specifically, in order from the object side to the image side, a lens group having a negative refractive power and a lens group having a positive refractive power are arranged as a whole.

  Specifically, at the zoom position at the wide-angle end, the combined refraction of the first lens unit L1 having the negative refractive power, the second lens unit L2, the third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5. The paraxial refractive power of each lens group is set so that the force becomes a positive refractive power. The fourth lens unit L4 having a negative refractive power so that the image-side principal point in the synthesis system of the second lens unit L2, the third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5 is located closer to the image side. Is positioned on the object side so that the back focus in the entire system becomes long.

  On the other hand, at the telephoto end zoom position, the entire lens system is set to be of the telephoto type (teletype) in order to shorten the total lens length of the entire system. In other words, the lens side has a positive refractive power lens group and a negative refractive power lens group in order from the object side to the image side so that the image side principal point is located closer to the object side. Specifically, the first lens unit L1 having a negative refractive power, the second lens unit L2 having a positive refractive power, and the third lens unit L3 having a positive refractive power are brought close to each other at the zoom position at the telephoto end. Each lens group has a positive combined refractive power.

  Further, the fourth lens unit L4 having a negative refractive power and the fifth lens unit L5 having a positive refractive power are brought close to each other so that the combined refractive power as a whole becomes negative. As a result, the entire system constitutes a telephoto type lens system, thereby shortening the total lens length at the telephoto end.

  In each embodiment, the focal length of the entire system at the wide-angle end is fw, and the focal length of the image stabilizing lens unit Gis is fis. The distance on the optical axis from the image side lens surface of the image stabilizing lens unit Gis to the aperture stop SP is represented by Dis. The distance on the optical axis from the most object-side lens surface to the most image-side lens surface at the wide-angle end is defined as DLw.

At this time,
1.5 <| fis / fw | <9.5 (1)
0.00 <Dis / DLw <0.25 (2)
The following conditional expression is satisfied. Next, the technical meaning of each conditional expression will be described.

  Conditional expression (1) appropriately defines the ratio of the focal length (the reciprocal of the refractive power) of the image stabilizing lens unit Gis to the focal length of the entire system, and aberration variation during image stabilization by the image stabilizing lens unit Gis. Is to reduce If the absolute value of the focal length of the anti-vibration lens unit Gis becomes smaller than the lower limit of the conditional expression (1), a lot of decentration aberrations occur during the anti-vibration, and the optical performance deteriorates. Further, if the absolute value of the focal length of the image stabilization lens unit Gis exceeds the upper limit of the conditional expression (1), the image stabilization sensitivity becomes too low, and the component in the direction perpendicular to the optical axis during image stabilization. This is not good because the drive amount becomes larger and the drive mechanism becomes larger.

  Conditional expression (2) is for making the distance on the optical axis from the lens surface on the aperture stop SP side in the image stabilizing lens unit Gis to the aperture stop SP appropriate. When the anti-vibration lens unit Gis and the aperture stop SP are separated beyond the upper limit of the conditional expression (2) and the anti-vibration lens unit Gis approaches the object side, the off-axis light beam passing through the anti-vibration lens unit Gis from the optical axis is incident. Height increases. As a result, the aberration fluctuation of the off-axis light beam at the time of anti-vibration increases and the lens diameter becomes large, and high-precision drive control becomes difficult.

  When the vibration-proof lens portion Gis approaches the aperture stop SP nearing the lower limit of the conditional expression (2), the aperture stop SP and the vibration-proof lens portion Gis are likely to interfere with each other, and the effective diameter of the aperture stop SP is controlled. Therefore, it is not possible to secure a sufficient arrangement space for the diaphragm device. Also, the device itself is not good because it becomes larger in the direction of the outer diameter. In each embodiment, it is more preferable to set the numerical ranges of conditional expression (1) and conditional expression (2) as follows.

1.7 <| fis / fw | <9.0 (1a)
0.00 <Dis / DLw <0.20 (2a)
According to each embodiment, specifying the lens configuration as described above reduces the load on the driving means for vibration compensation (anti-vibration), facilitates downsizing of the entire apparatus, and effectively performs vibration compensation. A zoom lens that can be obtained is obtained.

  In each embodiment, it is more preferable to satisfy one or more of the following conditions. The length on the optical axis of the anti-vibration lens unit Gis is assumed to be Lis. At the time of focusing, the second lens unit L2 moves, and the focal length of the second lens unit L2 is set to f2. Let bfw be the back focus at the wide-angle end. At this time, it is preferable to satisfy one or more of the following conditional expressions.

0.008 <Lis / DLw <0.200 (3)
1.2 <f2 / fw <9.0 (4)
0.30 <fw / bfw <0.70 (5)
Next, the technical meaning of each conditional expression described above will be described.

  Conditional expression (3) is for reducing the size of the image stabilizing lens unit Gis. Conditional expression (3) defines the ratio between the length Lis on the optical axis of the image stabilizing lens unit Gis and the distance DLw on the optical axis from the first lens surface to the final lens surface of the zoom lens LA within an appropriate range. ing. When the upper limit of the conditional expression (3) is exceeded and the length on the optical axis of the anti-vibration lens unit Gis is too long, the mechanism for anti-vibration becomes large. If the lower limit of the conditional expression (3) is exceeded and the length on the optical axis of the anti-vibration lens unit Gis is too short, a lens shape that makes it difficult to process each lens constituting the anti-vibration lens unit Gis is obtained.

  Conditional expression (4) defines the focal length of the second lens unit L2 for focusing within an appropriate range. If the upper limit of conditional expression (4) is exceeded and the focal length of the second lens unit L2 for focusing becomes too long, the amount of movement that moves during focusing increases, making it difficult to downsize the entire system. If the lower limit of conditional expression (4) is exceeded and the focal length of the second lens unit L2 for focusing becomes too short, aberration fluctuations during focusing increase, and error sensitivity increases in assembling the second lens unit L2. It becomes higher and assembly adjustment becomes difficult.

  Conditional expression (5) defines the ratio of the focal length of the entire system at the wide-angle end to the back focus at the wide-angle end in an appropriate range. This is a condition that can be sufficiently applied to a camera that requires a sufficiently long back focus even though it is a wide-angle zoom lens. Here, the back focus is the distance from the lens surface on the image side to the paraxial image surface of the lens (optical element) having the curvature (power) that is closest to the image side.

  If the back focus is too short beyond the upper limit of conditional expression (5), it is not preferable because it interferes with the camera. If the lower limit of conditional expression (5) is exceeded and the back focus becomes too long, the total lens length at the wide-angle end increases, making it difficult to downsize the entire system. In addition, the retrofocus type is too strong as a lens type, and distortion is increased particularly at the wide-angle end, making this correction difficult. More preferably, the numerical ranges of conditional expressions (3) to (6) are set as follows.

0.010 <Lis / DLw <0.150 (3a)
1.5 <fF / fw <8.5 (4a)
0.35 <fw / bfw <0.65 (5a)
In each embodiment, the first lens unit L1 includes a positive lens, a negative lens, a negative lens, and a positive lens in order from the object side to the image side. The second lens unit L2 is composed of one positive lens. The fourth lens unit L4 includes a cemented lens in which a positive lens and a negative lens are cemented. The fifth lens unit L5 includes a positive lens and a cemented lens in which a positive lens and a negative lens are cemented. Focusing from infinity to short distance is performed by moving the second lens unit L2 to the image side.

  In Example 1, the third lens unit L3 includes, in order from the object side to the image side, a cemented lens of a negative lens and a positive lens, and an anti-vibration lens unit Gis. The anti-vibration lens unit Gis is composed of one positive lens having a biconvex shape. As is apparent from the respective aberration diagrams, in the first embodiment, various aberrations are well corrected including during image stabilization.

  In Example 2, the third lens unit L3 includes, in order from the object side to the image side, a positive lens and an anti-vibration lens unit Gis. The anti-vibration lens unit Gis is composed of a cemented lens in which a negative lens and a positive lens are cemented. As is apparent from the respective aberration diagrams, in the second embodiment, various aberrations are well corrected including during image stabilization.

  In Example 3, the third lens unit L3 includes, in order from the object side to the image side, a cemented lens in which a negative lens and a positive lens are cemented, and an anti-vibration lens unit Gis. The anti-vibration lens unit Gis is composed of one negative lens having a concave lens surface on the image side. As is apparent from each aberration diagram, in Example 3, various aberrations are well corrected including during image stabilization.

  In Example 4, the third lens unit L3 includes a negative lens and an image stabilizing lens unit Gis in order from the object side to the image side. The anti-vibration lens unit Gis is composed of a cemented lens in which a negative lens and a positive lens are cemented. As is apparent from each aberration diagram, in Example 4, various aberrations are well corrected including during image stabilization.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  Next, an embodiment in which the zoom lens of the present invention is used as an imaging optical system in a single-lens reflex camera system (imaging apparatus) (optical apparatus) will be described with reference to FIG. In FIG. 13, 10 is a single-lens reflex camera body, and 11 is an interchangeable lens equipped with a zoom lens according to the present invention. Reference numeral 12 denotes a recording unit such as a film or an image sensor for recording a subject image obtained through the interchangeable lens 11. Reference numeral 13 denotes a finder optical system for observing a subject image from the interchangeable lens 11, and reference numeral 14 denotes a rotating quick return mirror for switching the subject image formed by the interchangeable lens 11 to the recording means 12 and the finder optical system 13 for transmission. is there.

  When observing the subject image with the finder optical system 13, the subject image formed on the focus plate 15 via the quick return mirror 14 is converted into an erect image with the pentaprism 16 and then magnified with the eyepiece optical system 17. .

At the time of shooting, the quick return mirror 14 rotates in the direction of the arrow, and the subject image is formed and recorded on the recording means 12. Reference numeral 18 denotes a submirror, and 19 denotes a focus detection device. Thus, by applying the zoom lens of the present invention to an imaging device such as an interchangeable lens such as a single-lens reflex camera, an imaging device having high optical performance can be realized. The zoom lens of the present invention can be similarly applied to a single-lens reflex camera without a quick return mirror.

Hereinafter, specific numerical examples 1 to 4 of the zoom lenses of Examples 1 to 4 will be described. i indicates the order of the optical surfaces counted from the object. The surface number i is counted in order from the object side. ri is the radius of curvature (mm) of the i-th surface, and di is the distance between the i-th and i + 1-th surfaces (mm). ndi and νdi represent the refractive index and Abbe number of the medium between the i-th surface and the (i + 1) -th surface with respect to the d-line, respectively. BF is back focus. The total lens length represents the distance from the first lens surface to the image plane.

  An aspheric surface is represented by adding a symbol * after the surface number. In the aspherical shape, X is the amount of displacement from the surface vertex in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, r is the paraxial radius of curvature, K is the conic constant, A4, A6, When A8, A10, A12... Are aspherical coefficients of respective orders,

Represented by “E ± XX” in each aspheric coefficient means “× 10 ± ^XX ”. Table 1 shows numerical values corresponding to the aforementioned conditional expressions.

(Numerical example 1)
Unit mm

Surface data surface number rd nd νd Effective diameter
1 72.277 4.87 1.48749 70.2 40.33
2 -2104.636 0.15 38.09
3 76.624 1.60 1.69680 55.5 33.30
4 14.581 8.47 24.69
5 -273.463 1.20 1.59522 67.7 24.06
6 30.268 0.15 23.14
7 20.148 2.74 1.84666 23.9 23.29
8 30.461 (variable) 22.60
9 419.932 1.76 1.83481 42.7 12.85
10 -99.962 (variable) 13.00
11 18.001 0.95 1.74077 27.8 14.65
12 11.775 4.68 1.48749 70.2 14.22
13 -70.678 1.18 14.14
14 146.126 1.11 1.61800 63.3 13.88
15 -197.632 0.50 13.77
16 (Aperture) ∞ (Variable) 13.61
17 -25.348 3.99 1.84666 23.9 11.23
18 -10.786 0.80 1.72047 34.7 11.44
19 74.387 (variable) 11.40
20 138.172 1.30 1.52996 55.8 15.80
21 * -213.969 0.21 16.18
22 -140.978 2.91 1.59522 67.7 16.18
23 -17.054 1.00 1.84666 23.9 16.59
24 -23.826 (variable) 17.35
Image plane ∞

Aspheric data 21st surface
K = 0.00000e + 000 A 4 = 2.60681e-005 A 6 = 4.22428e-008 A 8 = -7.01418e-011 A10 = -4.06736e-012 A12 = 4.22328e-014

Various data Zoom ratio 2.86
Wide angle Medium Telephoto focal length 18.63 30.51 53.30
F number 3.63 4.23 5.88
Half angle of view (degrees) 36.25 24.12 14.37
Image height 13.66 13.66 13.66
Total lens length 124.97 118.67 128.17
BF 35.30 46.55 68.40

d 8 31.10 12.20 2.00
d10 8.24 9.59 7.45
d16 3.81 6.64 9.75
d19 6.94 4.11 1.00
d24 35.30 46.55 68.40

(Numerical example 2)
Unit mm

Surface data surface number rd nd νd Effective diameter
1 70.290 4.49 1.48749 70.2 40.53
2 2114.636 0.15 38.65
3 62.136 1.60 1.73400 51.5 33.34
4 14.996 8.20 25.11
5 -137.915 1.20 1.59522 67.7 24.68
6 29.456 0.15 23.66
7 22.178 2.90 1.84666 23.9 23.80
8 37.984 (variable) 23.19
9 -1702.442 1.09 1.83400 37.2 12.84
10 -104.098 (variable) 12.66
11 28.533 1.58 1.74 100 52.6 14.96
12 54.746 0.20 14.87
13 22.996 0.80 1.73800 32.3 14.94
14 13.036 4.34 1.49700 81.5 14.50
15 -48.757 2.18 14.37
16 (Aperture) ∞ (Variable) 13.63
17 -24.971 3.93 1.80518 25.4 10.95
18 -10.675 0.80 1.72342 38.0 11.10
19 48.866 (variable) 11.51
20 53.953 1.60 1.52996 55.8 17.13
21 * -1005.068 0.28 17.50
22 -234.955 3.49 1.59522 67.7 17.50
23 -16.408 2.00 1.84666 23.9 17.91
24 -23.135 (variable) 19.26
Image plane ∞

Aspheric data 21st surface
K = 0.00000e + 000 A 4 = 2.52989e-005 A 6 = -2.40160e-008 A 8 = 1.06774e-009 A10 = -1.48801e-011 A12 = 7.02053e-014

Various data Zoom ratio 2.86
Wide angle Medium Telephoto focal length 18.63 29.97 53.30
F number 3.63 4.17 5.88
Half angle of view (degrees) 36.25 24.50 14.37
Image height 13.66 13.66 13.66
Total lens length 128.30 122.20 131.44
BF 35.30 46.53 68.34

d 8 29.94 10.79 1.20
d10 10.70 12.52 9.53
d16 4.44 7.00 10.39
d19 6.94 4.39 1.00
d24 35.30 46.53 68.34

(Numerical Example 3)
Unit mm

Surface data surface number rd nd νd Effective diameter
1 81.773 4.48 1.51633 64.1 38.08
2 -782.731 0.15 35.86
3 74.055 1.60 1.69680 55.5 31.54
4 14.420 8.00 23.90
5 -187.793 1.20 1.58913 61.1 23.38
6 30.355 0.15 22.63
7 20.577 2.79 1.84666 23.9 22.86
8 34.075 (variable) 22.25
9 113.362 1.78 1.67003 47.2 12.84
10 -71.356 (variable) 12.95
11 16.852 0.95 1.78470 26.3 13.67
12 10.837 4.68 1.51633 64.1 13.15
13 -47.981 0.25 12.96
14 305.795 1.00 1.62041 60.3 12.74
15 78.558 1.20 12.51
16 (Aperture) ∞ (Variable) 12.30
17 -19.360 3.31 1.84666 23.9 10.69
18 -10.834 0.80 1.62588 35.7 11.06
19 60.290 (variable) 11.09
20 89.135 1.50 1.52996 55.8 16.14
21 * -737.401 0.01 16.60
22 197.680 3.39 1.51633 64.1 16.67
23 -18.522 1.00 1.84666 23.9 17.11
24 -23.647 (variable) 17.79
Image plane ∞

Aspheric data 21st surface
K = 0.00000e + 000 A 4 = 2.54971e-005 A 6 = 3.87694e-008 A 8 = -3.98718e-010 A10 = 2.44713e-012

Various data Zoom ratio 2.63
Wide angle Medium Telephoto focal length 19.80 31.10 52.16
F number 3.63 4.30 5.88
Half angle of view (degrees) 34.60 23.71 14.68
Image height 13.66 13.66 13.66
Total lens length 121.49 117.00 125.13
BF 35.89 46.55 67.24

d 8 28.29 11.96 2.31
d10 9.14 10.31 7.40
d16 2.99 5.68 8.21
d19 6.94 4.25 1.72
d24 35.89 46.55 67.24

(Numerical example 4)
Unit mm

Surface data surface number rd nd νd Effective diameter
1 74.439 5.17 1.48749 70.2 42.48
2 -815.320 0.15 40.22
3 78.638 1.60 1.77250 49.6 34.20
4 15.176 8.20 25.36
5 -509.077 1.20 1.59522 67.7 24.84
6 32.302 0.15 24.07
7 21.069 2.86 1.84666 23.9 24.31
8 34.678 (variable) 23.72
9 98.053 1.56 1.71700 47.9 12.77
10 -89.064 (variable) 12.83
11 -29.837 1.41 2.00100 29.1 13.05
12 -34.943 0.99 13.49
13 27.921 0.80 1.65412 39.7 14.01
14 10.343 4.91 1.60 300 65.4 13.80
15 -49.336 (variable) 13.74
16 (Aperture) ∞ 4.25 11.77
17 -23.376 3.42 1.84666 23.9 10.98
18 -10.300 0.80 1.72047 34.7 11.23
19 81.122 (variable) 11.27
20 68.868 1.60 1.52996 55.8 16.43
21 * -160.887 0.34 16.79
22 -84.310 3.20 1.59522 67.7 16.80
23 -15.352 1.00 1.84666 23.9 17.22
24 -21.730 (variable) 18.12
Image plane ∞

Aspheric data 21st surface
K = 0.00000e + 000 A 4 = 2.58514e-005 A 6 = -1.61104e-008 A 8 = 1.25850e-009 A10 = -2.11335e-011 A12 = 1.16959e-013

Various data Zoom ratio 2.86
Wide angle Medium Telephoto focal length 18.63 31.07 53.30
F number 3.63 4.36 5.88
Half angle of view (degrees) 36.25 23.73 14.37
Image height 13.66 13.66 13.66
Total lens length 126.92 120.66 128.85
BF 35.30 46.57 68.44

d 8 32.37 11.84 1.03
d10 6.21 9.21 6.34
d15 2.47 5.76 8.42
d19 6.94 3.66 1.00
d24 35.30 46.57 68.44

Gis Anti-Vibration Lens L1 First Lens Group L2 Second Lens Group L3 Third Lens Group L4 Fourth Lens Group L5 Fifth Lens Group

Claims (12)

In order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, an aperture stop, a fourth lens group having a negative refractive power, and a positive A zoom lens that includes a fifth lens unit having refractive power, and in which the interval between adjacent lens units changes during zooming,
The third lens group includes a vibration-proof lens unit that moves in a direction having a component perpendicular to the optical axis during image blur correction. The focal length of the entire system at the wide-angle end is fw, and the image stabilization The focal length of the lens unit is fis, the distance on the optical axis from the image side lens surface of the image stabilizing lens unit to the aperture stop is Dis, and from the most object side lens surface to the most image side lens surface at the wide angle end. When the distance on the optical axis is DLw,
1.5 <| fis / fw | <9.5
0.00 <Dis / DLw <0.25
A zoom lens satisfying the following conditional expression: When the length on the optical axis of the anti-vibration lens unit is Lis,
0.008 <Lis / DLw <0.200
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the second lens group moves during focusing and the focal length of the second lens group is f2,
1.2 <f2 / fw <9.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The zoom lens according to any one of claims 1 to 3, wherein the second lens group includes one positive lens. When the back focus at the wide angle end is bfw,
0.30 <fw / bfw <0.70
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   6. The zooming from the wide-angle end to the telephoto end, the second lens group, the third lens group, the fourth lens group, and the fifth lens group move to the object side. The zoom lens according to any one of the above.   7. The zoom lens according to claim 1, wherein the first lens unit moves along a locus convex toward the image side during zooming from the wide-angle end to the telephoto end.   8. The third lens group according to claim 1, wherein the third lens group includes a cemented lens in which a negative lens and a positive lens are cemented in order from the object side to the image side, and a positive lens. Zoom lens.   The said 3rd lens group is comprised from the cemented lens which cemented the positive lens and the negative lens, and the positive lens in order from the object side to the image side. Zoom lens.   8. The third lens group according to claim 1, wherein the third lens group includes a cemented lens and a negative lens in which a negative lens and a positive lens are cemented in order from the object side to the image side. Zoom lens.   The said 3rd lens group is comprised from the cemented lens which joined the negative lens and the negative lens, and the positive lens in order from the object side to the image side. Zoom lens.   An imaging apparatus comprising the zoom lens according to claim 1.